Ternary coupling

Figure 4-1. Chemical diffusion of a (ternary) couple with linear geometry. Initial compositions are c° and c°. Schematic diffusion (reaction) path.

An important report of new reactivity of this type involves the palladium-catalyzed ternary coupling of various aryl bromides, such as -bromotoluene, and PhSnBus with 9 and other simple dioxoles to give dioxolanes 91 (Equation 1) <1995SL1225>. 

Oda et al. have reported other ternary couplings. One (Scheme 4-39) involves phenyltributyltin, aryl bromides and 1,3-dioxole [135] (their original reaction involved norbornene). The second (Scheme 4-40) is in effect a double addition to non-terminal... 

Z-tamoxifen 403 tandem cyclization 290, 295 tandem Heck reaction-anion capture 253-4 tandem Heck reaction-phenoxide capture 253 tandem Heck reactions 251, 252-4 tandem intramolecular Heck-intermolecular Stille cross-coupling 255 taxol 140, 143,243,245 ( )-tazettine 146,234 telomerization 352 telomerization products 343, 345 template effect 140 teraconic anhydride 468 terminal acetylenes, synthesis of 216-20 terminal alkynes 6, 213 terminal 2,2-diorgano-l-aIkcnylboronates 51 terminal diynes 207 ternary complex 444 ternary coupling 177... 

Oda et al. have reported a ternary coupling involving norbomadiene, a vinyltin and a vinyl iodide (Scheme 4-25), which is proposed as a model for leukotriene synthesis [71]. 

Besides norbomene and norbomadiene, 1,3-dioxolenes are possible partners in these ternary couplings. Hence, starting from unsubstituted or 2-substituted 1,3-dioxolene, tri-butylphenyltin, and various bromoarenes, ci5-4,5-disubstituted 1,3-dioxolanes are obtained in good yields (Scheme 7). ... 

Hg Cd Te is an example of a ternary detector, in which the value of x controls the cutoff wavelength. Photoconductive detectors are generally simpler to couple to low noise amplifiers photodiodes generally have lower power consumption because these have no external bias, and better high frequency performance (15,16). 

The ternary complex model followed by the extended ternary complex model were devised to describe the action of drugs on G-protein-coupled receptors. 

Extended ternary complex model, a modification of the original ternary complex model for GPCRs (J. Biol. Chem. 268, 4625-4636, 1993) in which the receptor is allowed to spontaneously form an active state that can then couple to G-proteins and produce a physiological response due to constitutive activity. 

Metal-induced reductive dimerization of carbonyl compounds is a useful synthetic method for the formation of vicinally functionalized carbon-carbon bonds. For stoichiometric reductive dimerizations, low-valent metals such as aluminum amalgam, titanium, vanadium, zinc, and samarium have been employed. Alternatively, ternary systems consisting of catalytic amounts of a metal salt or metal complex, a chlorosilane, and a stoichiometric co-reductant provide a catalytic method for the formation of pinacols based on reversible redox couples.2 The homocoupling of aldehydes is effected by vanadium or titanium catalysts in the presence of Me3SiCl and Zn or A1 to give the 1,2-diol derivatives high selectivity for the /-isomer is observed in the case of secondary aliphatic or aromatic aldehydes. 

A variety of such ternary catalytic systems has been developed for diastereoselective carbon-carbon bond formations (Table). A Cp-substituted vanadium catalyst is superior to the unsubstituted one,3 whereas a reduced species generated from VOCl3 and a co-reductant is an excellent catalyst for the reductive coupling of aromatic aldehydes.4 A trinuclear complex derived from Cp2TiCl2 and MgBr2 is similarly effective for /-selective pinacol coupling.5 The observed /-selectivity may be explained by minimization of steric effects through anti-orientation of the bulky substituents in the intermediate. 

Figure 1. LRG States. One dimension represents LR coupling (top, L+R uncoupled bottom, LR coupled) another represents RG coupling (front, RG coupled back, R+G uncoupled) the third ("plane of interconversion") represents G interaction with nucleotide (bound, "G ", on left G vacant, G , on right). The available evidence suggests that activation proceeds through LRG (first bound to GDP, lower front left), LRG (vacant G in a ternary complex, lower front right), LRG (adding GTP, lower front left), then LR+G (now activated, lower rear left).

The ternary system consisting of a metallic catalyst, a chlorosilane, and a stoichiometric co-reductant has been reported by us for the first time to achieve the catalytic pinacol coupling. The homo coupling of aliphatic aldehydes is catalyzed by CpV(CO)4, Cp2VCl2, or Cp2V in the presence of a chlorosilane and Zn in DME to give the 1,3-dioxolanes 1 via the coupling and acetalization (Scheme 3) [18,19]. 

Cp2ZnCl2 similarly catalyzes the coupling reaction of aromatic aldehydes and ketones [36]. Another ternary-component system consists of a catalytic... 

The Cp2VCl2/R3SiCl/Zn catalytic system can be used for the reductive coupling of the imines 29 (Scheme 18) [55]. These components of the ternary catalyst are essential and, interestingly, meso-diastereoselectivity is observed in contrast to the coupling with cat. Cp2TiCl2/Sm system. The selectivity de-... 

Here, the agonist-receptor complex (AR) combines with a G-protein (G) to form a ternary complex (ARG ), which can initiate further cellular events, such as the activation of adenylate cyclase. However, this simple scheme (the ternary complex model) was not in keeping with what was already known about the importance of isomerization in receptor activation (see Sections 1.2.3 and 1.4.3), and it also failed to account for findings that were soon to come from studies of mutated receptors. In all current models of G-protein-coupled receptors, receptor activation by isomerization is assumed to occur so that the model becomes ... 

The interaction between Ag+ and selenium in the bloodstream has been studied in vitro by means of the HPLC-inductively coupled argon plasma-mass spectrometry (ICPMS) method. The metal ions and selenide form the unit complex (AgSe) and then this unit binds to selenoprotein to form the ternary complex [(AgSe)ra] selenoprotein in the bloodstream.1042... 

Ternary Pd-catalyzed coupling reactions of bicyclic olefins (most often norbor-nadiene is used) with aryl and vinyl halides and various nucleophiles have been investigated intensively over the past few years [44]. A new approach in this field is to combine Heck and Suzuki reactions using a mixture of phenyliodide, phenyl-boronic acid and the norbornadiene dicarboxylate. Optimizing the conditions led to 84% of the desired biphenylnorbornene dicarboxylate [45]. Substituted phenyl-iodides and phenylboronic acids can also be used, though the variation at the norbornadiene moiety is highly limited. 

A series of model siderophore molecular recognition studies coupled with host-guest carrier facilitated model membrane transport studies was reported (198-202). Three approaches were taken which incorporate (i) second coordination shell host-guest complexation, (ii) ternary complex formation, and (iii) a combination of ternary complex - second coordination shell host-guest complex formation. Examples of these approaches are described below. 

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